Category Archives: Ultrasonics

Are your Ultrasonics Powerful Enough?

Magnus Engineered Equipment (MEE) produces the most powerful ultrasonics for cleaning applications.  MEE manufactures ultrasonic transducers which operate at 20 kHz which is 25 times more powerful than the 40 kHz transducers supplied by other suppliers of cleaning equipment.  The transducers are made with continuously laminated magnetostrictive 20 kHz elements which deliver more uniform cleaning than the discretely mounted piezoelectric elements used in 40 kHz transducers.

Figure 1


Comparison of 20 kHz vs 40 kHz Ultrasonics with Household Aluminum Foil

Figure 1 shows the difference in cleaning power between the two types of transducers.  The 20 kHz transducer will perforate and tear the soft household aluminum foil whereas the less powerful 40 kHz transducers will only dimple the aluminum foil.

Figure 2 shows the difference in construction of 20 and 40 kHz transducers.  The weaker 40 kHz transducers are bonded to a thin stainless steel sheet to minimize the loss of energy from the piezoelectric elements.  The weak stainless can readily flex between the elements and thus transfer the energy to the cleaning solution.  This thin stainless steel sheet is prone to develop porosity and limits the 40 kHz transducer to a lifetime of 2-3 years.  The more powerful 20 kHz elements are continuously bonded to a thick stainless steel sheet which prevents porosity and greatly extends the life of the transducer.  The uniform bonding delivers a more uniformly sonicated cleaning solution which in turn delivers more uniform cleaning.

Figure 2

Polyurethane Mold Cleaning

Urethanes are an adhesive and will bond to aluminum or steel molds.  Over time, the molds used in the casting of urethane and polyurethane parts build up a residue and require cleaning.  Magnus Engineered Equipment (MEE) can provide a cleaning process wherein the molds are cleaned in less than 5 minutes and without any damage or distortion to the mold.  Dis-assembly of the mold is not required for cleaning.  Any size or weight mold can be cleaned with the MEE cleaning process.

In the past, producers of molded urethane parts would use an abrasive or grit blasting to clean the molds after casting.  This cleaning process caused the mold surface to become rougher which then made mold release and mold cleaning even more difficult.  These cleaning processes often required dis-assembly of the mold and many hours of effort to remove the surface contamination.  Using 20 kHz magnetostrictive transducer technology, MEE can provide a cleaning process which will clean the mold without dis-assembly, cause no harm to the mold, and will clean the mold in less than 5 minutes!

MEE manufactures and supplies the most powerful ultrasonic cleaning equipment for cleaning applications.  Unlike the commonly used piezoelectric transducers which operate at 40 kHz, MEE supplied magnetostrictive transducers which operate at 20 kHz and deliver ~25 times more cleaning power than piezoelectric transducers.  Higher power equates to more thorough cleaning, faster cleaning speeds, or both.  Figure 1 shows the cleaning power comparison between MEE’s magnetostrictive transducers and piezoelectric transducers.

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Figure 1 Magnus vs Competitor’s Ultrasonic Cleaning Power

 

Here are some photos of molds with polyurethane contaminant which were cleaned with the MEE process. 

Before Cleaning After Cleaning

Ultrasonic Frequency in Cleaning Applications

In the simplest terms,

ULTRASONIC CLEANING FREQUENCY = CLEANING POWER

Properly applied, ultrasonics can perform a more thorough, more complete cleaning job than any other cleaning method. Ultrasonics is a non-destructive method of cleaning which utilizes sound waves to form and implode vapor pockets on the surface of contaminated parts. This implosion results in the release of stored energy that creates a virtual scrubbing or cleaning action on the surface of the part to be cleaned.

In ultrasonic cleaning, the pressure phase of a sound wave is used to provide the cleaning action. Sonication creates areas in the liquid where negative pressure exists. At these points on the part to be cleaned, thousands of minute vapor bubbles are formed and these bubbles effectively scrub the part. As the ultrasonic energy level alternates (a half second later) the pressure in this same zone becomes positive and the vapor bubbles implode. This implosion (the bubbles bust inwardly) occurs with great violence. This action is commonly called “cavitation” and is not to be confused with the formation of air bubbles caused by degassing of water. While the quantity of energy in any one implosion is extremely small, it is calculated that enormous pressures in the order of 10,000 pounds per square inch and extreme temperatures of approximately 20,000 oF are generated. This cavitational activity–the formation and bursting of these vapor pockets–actually forms the scrubbing or cleaning action on the surface of the part.

Power Sonics TM Ultrasonic Transducers – A Magnus Engineered Equipment Exclusive

Power SonicsTM ultrasonic transducers are mechanically strong and capable of handling large amounts of power – a desirable feature when difficult cleaning jobs are encountered. Power SonicsTM operate at a frequency of 20 kHz whereas conventional sonic cleaning systems operate at 25 or 40 kHz. To see the difference in cleaning power, we need to examine the following chart.

Ultrasonic Cleaning Power

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Note that the “y-axis” is the relative strength or cleaning power of the ultrasonic system.

Ultrasonics running at 20 kHz are 5 times stronger than those running at 25 kHz and about 20 times stronger than those running at 40 kHz.

Greater cleaning power allows for faster cleaning speeds, more efficient cleaning, and the ability to clean the toughest substrates.